We are testing hypotheses about the synaptic organization of the stomatogastric system of crustaceans and the meaning of this organization for the production of motor patterns. These hypotheses are based on an extensive description of this organization. We are studying the sensory modulation of these patterns, and analyzing the neuronal networks of the ganglion with a digital-computer model to examine the significance of synaptic dynamics for reatures of the motor patterns. We are studying the structure of stomatogastric neurons, and measuring their membrane resistances, input resistances and voltage attenuation to quantify these properties important for synaptic integration.